The Other Holmes
by Reichenfeels
Summary: Good God, there's two of them. just a cracky little fic from yours truly
1. Chapter 1

John realized that something was awry the moment he stepped down the final stair into the living room of the flat to find it spotlessly clean. Every paper, every months-old clue tacked on the wall, had been either straightened or completely hidden from view, and the doctor nearly went back up to his room and into bed at the sight of it. Sherlock was in front of the far window, playing something light and energized on his violin, completely ignoring him.

"What's going on, then?" John sighed, rubbing his forehead as he walked and plopped down in his chair.

"Visitor. Arriving soon, I'd wager. I would change if I were you, she's hardly one for lateness."

"Vis—_she_?" John blinked at him, but the detective kept his darkly-suited back to him, still playing the tune without a pause. After a moment of baffled questioning that was not in any way answered, he scoffed and trudged up the stairs to change. Once safely back into his bedroom, he sat on his bed and frowned, thinking. Sherlock certainly never had visitors whom he invited over, and he certainly had never _cleaned _in expectation of them. He hadn't even believed Sherlock _could_ clean, since he had spent the better part of their living together picking up after the man like a mother hen. Shaking his head, he sighed and pulled a tan colored jumper over a deep green button-down, taking a hint from Sherlock's outfit that he should probably at least look decent. Pity, he had planned on spending the majority of his day drinking tea in his pajamas. Teeth and hair brushed, trousers buttoned, trainers tied to his feet, he came down the stairs and was again struck by how spotless the room was. Sherlock hadn't moved, of course, still playing agitated tunes on his violin.

Was he _nervous?_ John was baffled by the thought, having never seen Sherlock show such obvious concern toward a person's opinion, even his own. Overcome by curiosity once more, he opened his mouth to ask again when a light rapping sounded on the door. John, noting that Sherlock made no move to answer it, sighed and pulled open the door, and nearly dropped his jaw at the sight.

The woman standing in front of him was hauntingly familiar, though he was absolutely positive he'd never seen her before. He would _never_ forget such a distinctive face. She was tall and thin, her body seeming to buzz with energy despite her stillness, her angular face framed by a bob of glossy chocolate brown curls that made her wide crystal-like gray eyes shine brightly. Her full pink lips were pulled into a dazzling grin, "You must be Doctor Watson!" she cooed, her high voice ringing with a slight American accent, as if she had been abroad for many years, and all at once she had enveloped John into a tight hug. The instant the thin arms wrapped around him, he realized. _She looked exactly like Sherlock. _"Dear lord, Mycky told me you were acceptable but he didn't ever mention how _handsome_you were! And a soldier too, good lord." She tucked a curl behind her ear before her eyes slid to Sherlock. "Sherly!" Her high voice rose impossibly to a squeak, and John would have been tempted to cover his ears at the sound had he not been so distracted. Sherly? _Mycky?_ He stared at her in bafflement as she skipped across the room to his flatmate, who put his violin down and turned to her with an honest-to-god smile, accepting her hug.

"Katarina." He replied, deep voice warm, and she smacked his arm playfully. He smirked, the two of them seeming to exchange some sort of silent conversation, half of which John couldn't see, as the girl's back was to him. Finally, Sherlock's gray eyes went back to his baffled face, and he straightened. "John, allow me to introduce my little sister, Katarina."

"_Little sister._" She scoffed, turning to face John again, "I'm only two minutes younger, but he never lets me forget it. And please, call me Kate." Her smile was dazzling, and John was momentarily distracted.

"Sister." He finally choked, "You have a _twin sister that you've never mentioned?_" John glared at Sherlock, who gave an exasperated sigh.

"That's my fault, darling," Kate interjected smoothly, placing a light hand on her brother's arm to cut off the argument he was clearly about to make. "My existence is need-to-know only. My brothers do quite a job of protecting my anonymity. This is my first time back in the country in…oh, what is it, Sherly? Fifteen years?"

"Sixteen." He corrected quietly.

"Oh, quite right. The _Tête de Femme _robbery." Her expression became wistful.

"Sorry, _why _do you need to be anonymous?" John asked, completely in awe, realizing he was staring at her as he caught Sherlock glaring at him in his peripheral vision. The tall man placed a hand on the small of her back and led her to his own armchair, which she sat in gracefully, curling her long legs under her despite the short length of the charcoal-colored pencil skirt she was wearing.

"On record, I am a travel photographer. I have a blog and everything, it's quite extensive. I did this piece on food of the American south that was _divine_—" she cleared her throat, realizing she was trailing off, "Er, right. But I actually work for Mycroft, doing undercover research abroad. Prevent assassinations, recovering stolen Picasso works, things Sherly deems 'boring', you know." She gave John a conspiratorial wink, and Sherlock rolled his eyes.

"Ah. Right." John nodded, sitting in his own armchair across from her.

"You are unsurprised." She observed, smirking.

"You're a bloody Holmes, aren't you?" He replied before he could stop himself, but she laughed lightly.

"Yes I suppose the lot of us are rather addicted to danger. And sticking our noses where it doesn't belong." She sniffed, shrugging, "Sherly, dear, be a doll and get me some tea, would you?" she purred, turning her gaze to her brother. Much to John's disbelief, he actually nodded and strode into the kitchen, leaving the two alone. "So, Doctor Watson—"

"John. Just John." He interjected, flushing.

"John," she smiled sweetly, "Sherly has told me so much about you. I feel as though we are friends already." John was struck once again by her eyes, by how bloody similar she looked to his flatmate, though her personality was completely Sherlock's opposite. She was charming, her smiles easy, her voice high and dripping with genuine interest. Still, he couldn't get over the feeling that she was studying him with her conversation the way her brothers deduced things about him from his physicality. It was disconcerting.

"I wish I could say the same." He finally said lamely, and she shook her head, still smiling.

"Don't hold it against him. My brothers act disconnected from their humanity, but we'd do anything for each other." John frowned; he'd always assumed as much, at least from Mycroft, but it felt odd having it said out loud. He'd regarded the Holmes brothers' relationship to be a bit of an elephant in the room, knowing that they obviously cared about one another, but no one ever stating so outwardly. Sherlock made his reappearance then, placing a cup of tea in his sister's small, lithe fingers. John noted that it seemed to have more milk than actual tea in it, much like Sherlock preferred. This was too odd.

"I assume you had a reason for coming here." The detective said brusquely, standing next to her chair. She took a sip of the tea and placed it neatly back in its saucer on the table beside her before nodding, leaning forward to pluck the mustard-yellow leather tote bag she had brought with her off the floor. John didn't miss the little CC's on the patterned red scarf tied fashionably to one of the handles; exactly how much money did this bloody family have? Enough to where Sherlock certainly didn't need a flatmate. He huffed and crossed his arms, watching with interest as she pulled a black folder from the bag and handed it to Sherlock.

"He's on the move." She sighed, watching as Sherlock flipped through what looked like large photographs. "Those were taken in Miami. He boarded a plane to Moscow. I had Danielle attempt to intercept him, but he got in an unmarked vehicle and disappeared into the night upon arrival. Completely off the map."

Sherlock scoffed, "Why would you send _her_?"

"She happens to be my best agent—"

"Bloody flirt, that's what she is. Idiot."

"_And _my best friend." Kate added over her brother's skulking accusations, glaring at him. The two scowled at each other before he turned his attention back to the photographs.

"You believe he's headed back here." He finally said, and she nodded.

"Oi! As clever as you two are, mind letting me in here?" John snapped, growing frustrated. Two pairs of crystalline eyes turned to him, and he shifted uncomfortably.

"Moran, John. Keep up. I did _tell _you I had people in America trailing him." Sherlock rolled his eyes, tossing him the folder.

"When you said you had people trailing him, you didn't think to mention that person was your twin sister?" John accused, still bitter, as he flipped open the folder and went through the pictures. Most of them were slightly blurred images of a tall, thickly muscled blond man travelling through what seemed like a large airport.

"Is he always so angry?" Kate whispered, looking up at Sherlock, who grimaced.


	2. Chapter 2

It had been one of the strangest nights of John's life to date, and considering the fact that he shared a flat with Sherlock Holmes, that was truly saying a lot. After a fairly spectacular argument between the twins (which John had watched with a mix of fear and amusement) about where Katarina was to stay during the duration of her trip, the smaller Holmes finally won out, and Sherlock's bedroom had officially been coveted as her own, much to the detective's chagrin. After that had been settled, the luggage began to arrive, and John wasn't sure how such a seemingly down-to-earth woman could have _so many clothes_. Admittedly, at least three of the designer suitcases were filled with cameras and other necessary equipment, but at least four others were filled with an abundance of outfits for every sort of dress code imaginable, and John was briefly struck with the realization that many of the clothes were her own way of disguising herself, blending in with every sort of crowd. Finally, unable to handle the dark-haired duo's constant flip-flopping between bickering and half-internal conversations (apparently "twin telepathy" was not just a myth), he went upstairs to bed.

The next morning, John came down the stairs, a bit surprised to find Kate sitting cross-legged on the floor of the living room, an industrial-looking laptop in front of her. She was muttering to herself as she clicked on what looked like a blurry image on the screen, rendering it in an attempt to get some details out of it. "God _damn _it." She whispered in frustration, not turning to acknowledge John as he came down. Knowing better than to interrupt Sherlock when he was working, John decided to take the same approach with his sister, padding into the kitchen to find his flatmate, but to no avail. Nor was he in his bedroom or bathroom. Giving up, he came back into the living room in time to see Katarina slam her computer closed agitatedly, carding a hand through her short hair. Her angular face turned to him then, and she smiled pleasantly, "Oh! Morning, hon. Didn't hear you get up." John paused at her upbeat tone, having noted her clear frustration only moments before. She was already fully dressed in dark, perfectly fitted jeans and an emerald green blouse that exposed a tasteful amount of pale cleavage. She stood, stretching, her thin body just a bit taller than John's in the high-heels barely visible under the hem of her jeans. He had a hard time looking away.

"Sherlock home?" he finally asked lamely, watching her wearily as she scooped up her computer.

"Hmm? No, his friend called about some case. What's his name? The handsome inspector one…"

"Lestrade?" John asked, cocking his head in amusement.

"_Lestrade_! That's the one. I really ought to remember that." She shook her head, packing the computer away in a locking briefcase, snapping it closed.

"Er, right. Would you like to go get coffee, then?" he asked, feeling foolish. She turned to him and raised a delicate eyebrow, and John knew instantly what that look meant. He'd been rejected enough times to read the 'you're serious?' on her face. And besides, she was Sherlock's _sister. _His _twin_ sister, to be precise, and just based on the way he had glared at him for staring the night before proved that Sherlock's protective nature shone through when it came to Katarina. "Just, you know, I didn't even know you existed before yesterday." He clarified awkwardly, and she smiled again.

"Alright, then."

After John had changed into jeans and a jumper, they walked a few blocks up the road to a little French bistro, where Kate chose a table under a striped umbrella on the patio. John, sitting beside her, studied her wearily out of the corner of his eye. It was still odd to him, how terrifyingly similar to Sherlock her looks and movements were, how graceful she was in even the smallest movements. The waiter came up to them and he could see it in his eyes too, the way people stared at her unique, hauntingly beautiful face. The poor boy barely even glanced at John as he took their orders (Katarina pronouncing her order with the smooth confidence of a fluent French speaker, making John's own tongue feel heavy and lame in response), and he scurried off again, leaving them alone.

"So…what's your story, anyway? I mean, most girls don't grow up to be, er, _travel photographers_." He glanced around, knowing her job was a top-secret one, and she smirked at his apprehension.

"How much have my brothers told you about our family?" she finally asked, smiling sweetly up to the waiter as he set their coffees in front of them before turning her clear eyes to John.

"Nothing, really." He admitted, wrapping his hands around the mug without actually drinking from it.

"Well, to understand my brothers and I, you really ought to understand our parents. I'm sure you've realized by now we don't exactly come from a modest household." John grimaced at that, knowing that nearly everything Sherlock owned was name-brand or designer. "Our parents were extremely old-fashioned, our father coming from old money, plus his position in the government, giving us more money than they really knew what to do with. Our mother didn't work, exactly. She collected old books, had a little shop, but it was more of a hobby. That was what mummy believed a lady should have: a hobby and a husband and children. And she believed those children should be well versed in everything. And thus my brothers and I were given the greatest possible education, learning math and science and language. I wanted to play sports. Mummy hated it."

She sighed then, taking a box of cigarettes from her handbag and placing one between her lips before offering one to John, who refused with a small shake of his head, dreading the moment when Sherlock would find his sister's stash. With a shrug, she lit it and took a long drag, and John struck by the grace she brought to what he generally considered a dirty habit. Waving her hand absently, she sighed a smooth stream of smoke, "Anyway. It's obvious, I'm sure, that my brothers and I exhibit what is generally considered a high amount of brainpower. We think differently, see things differently. Obviously the three of us excelled in our schooling, though it was just Mycroft who actually pleased our parents with his career; my parents do not even know that I work with the boys. They think I travel taking photographs." She grinned briefly, and John had to return the expression. "We look out for eachother, my brothers and I. That's why I remain anonymous, because they knew that in doing so I could have my best chance of a happy life. And I _am _happy, though more so now that I know my twin brother is being looked after. He worries Mycroft and I, you know." John nodded. He _did _know, he had known since he first met Mycroft.

The way she had said it though, that 'he was being looked after' made John hesitate briefly before deciding to ask the question that had so often passed his mind in his time with Sherlock, "So, er, Sherlock's never had any sort of friend or relationship or anyone before that would, you know, care for him?"

Kate chuckled darkly, taking another drag from her cigarette, "You know him as well as I do. Sherlock doesn't _do _relationships, or at least he didn't. Though I'm surprised you haven't had this discussion with him yourself, what with you two being together for so long."

John blanched, "Sherlock and I are _not in a relationship_." He said defensively, looking down as her eyes (_his_ eyes) bore into him with a mix of confusion and amusement.

"Ah. One of those 'on-again, off-again' things? How very American of you." She stamped out her cigarette and took a sip from her coffee, smirking.

"No, one of those 'we were never on and therefore can never be off' things. I'm not gay, Katarina." John scowled, crossing his arms over his chest. Here he was, still harboring the slightest hope that this beautiful woman would be interested in him, and the entire time she had been under the impression that he was shagging her brother. It was humiliating, to say the least.

"But…that's not right at all, the way he talks about you…" her voice was barely above a whisper, full lips in a little O of surprise. "Oh, my poor sweet Sherlock."

"Excuse me? What the hell do you mean 'poor Sherlock'?" he was beginning to get angry and frustrated, hating the look of pity on her face.

"Yes, poor Sherlock. Poor Sherlock who is in love with a man so incredibly thick that he cannot even fathom the thought of a relationship with him. Poor Sherlock who shuts everyone out, but chooses to let in the one person who can, and probably does, hurt him the most. To love someone who you believe will never love you back…he's stronger than I give him credit for." She pulled out her phone then, sending a text with agitated movements.

"Sherlock isn't…he's not _in love _with me." John said, lamely, panicking a bit at her clear animosity.

"Oh? So he popped off a building because of his respect for your taste in jumpers?" she shot back, glaring now, protective.

"That wasn't just for me." He replied smally.

"How many phonecalls did he make on that rooftop, Doctor Watson?" she said darkly, standing as a black car rolled around the corner, and striding to the curb and into the back seat without so much as a second glance, leaving John alone and confused on the patio.


End file.
